The 22-year-old, who joined Liverpool from Tottenham in 2014, made his first-team debut in the FA Cup third round in January.
Stewart told the club’s official website: “It gives me more confidence, it shows [the club] believes in me and believe that I could go on to become a good player for them.
“It has just given me confidence in myself and the security [I have] time to prove myself and get better with good coaches and good players.”
